Three years' ago had the 'flu jab and a couple of weeks later had severe breathing problems, this was because my underactive thyroid went overactive which was the cause of my breathing problems! After this experience, did not want the 'flu jab.
I cannot forget, however, my mother once had the 'flu and she was very ill and ended up in hospital. It was very frightening.
Had the 'flu jab last year on a Saturday and just had a sore arm, but by the evening had a temperature, which was bearable, took some paracetamol and also on the Sunday and stayed in bed all day. The following Monday was right as rain. Am booked in for the 'flu jab next Saturday and will take some paracetamol once home.